JP2006137163A - Apparatus for manufacturing molded product - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress as much as possible temperature rising of a cylinder 21 even when the temperature of a molten resin is high. <P>SOLUTION: The apparatus for manufacturing a molded product is provided with an upper and a lower molds 12 for forming a cavity 13, a hot runner block 17 in which a first resin passage 16 is formed, a gate nozzle 19 in which a second resin passage 18 communicating the first resin passage 16 and the cavity 13 is formed, a gate pin 20 for opening/closing the second resin passage 18, and a cylinder 21 for driving the gate pin 20. The cylinder 21 is installed to the hot runner block 17 via a cooling plate 45 having a passage 48 through which cooling water flows. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a molded product manufacturing apparatus for manufacturing a molded product by injection molding.

  Conventionally, injection molding is suitable for mass production of thermoplastic resin molded products and has been applied to the production of various molded products. For example, large products such as automobile bumpers and door trims are manufactured by injection molding, but such molded products using a large amount of thermoplastic resin are generally produced by a hot runner type molded product manufacturing apparatus having a plurality of gates. Manufactured (see, for example, Patent Document 1).

  The molded product manufacturing apparatus includes, for example, an upper mold that is a movable mold that moves up and down, and a lower mold that is a fixed mold that does not move. The lower mold has a resin supply section for supplying a molten resin into a molding cavity formed by the upper mold and the lower mold.

  Here, the resin supply unit will be described with reference to FIG.

  The resin supply unit 101 includes a hot runner block 112, two gate nozzles 114, two cylinders 115, and two valve pins 116.

  Inside the hot runner block 112, a resin passage 118 extending in the horizontal direction (left and right in FIG. 8) is formed, and the resin passage 118 is connected to an injection machine (not shown) via a port 125.

  The gate nozzle 114 is formed of a cylindrical body having a resin passage 119 formed therein and extending in the vertical direction, and is mounted on both left and right ends of the hot runner block 112. The resin passage 119 of the gate nozzle 114 communicates with the resin passage 118 of the hot runner block 112 at the lower end of the gate nozzle 114, and communicates with a molding cavity (not shown) at the upper end of the gate nozzle 114. Yes. A resin supply port 121 is formed at the upper end of the gate nozzle 114 by reducing the inner diameter of the resin passage 119.

  The cylinders 115 are disposed below the gate nozzles 114, and are attached to the lower surface of the hot runner block 112 via a collar 122, a cylinder fixing plate 123, and a heat insulating material 124.

  The valve pin 116 is connected to the cylinder 115 and extends vertically. The resin 115 is driven to move up and down by the cylinder 115 so as to open and close the resin supply port 121.

With the above configuration, the resin supply unit 101 opens and closes the resin supply port 121 by driving the valve pin 116 to supply the molten resin in the resin passage 118 of the hot runner block 112 into the cavity. At this time, since the heat insulating material 124 is interposed between the hot runner block 112 and the cylinder 115, the temperature rise of the cylinder 115 is suppressed even when the hot runner block 112 becomes high temperature.
JP 2004-58374 A

  By the way, in recent years, glass fibers are mixed in a molten thermoplastic resin in order to increase the strength of a resin molded product and replace the conventional iron plate. In this case, in order to smoothly flow the molten resin in the resin passage, it is necessary to heat to a temperature (for example, about 240 ° C. to 260 ° C.) higher than a general temperature (for example, about 200 ° C. to 240 ° C.). Become.

  Then, even if the heat insulating material 124 is provided between the hot runner block 112 and the cylinder 115 as in the conventional case, the temperature of the cylinder 115 itself is raised to, for example, about 100 ° C., so that it is provided at the sliding portion of the cylinder 115. The sealing member that has been deteriorated by heat. Therefore, the sealing member is changed from a general fluorine-based material to an expensive hydrogenated nitrile-based material having heat resistance.

  However, even when a hydrogenated nitrile-based seal member is used, the seal member cannot be completely prevented from being thermally deteriorated, resulting in a malfunction of the cylinder. Therefore, it is necessary to periodically disassemble the mold and replace the seal member with a new one. However, disassembling this mold is difficult because of the skill of the operator, and requires a relatively long working time. End up.

  The present invention has been made in view of such various points, and an object thereof is to suppress the temperature rise of the cylinder as much as possible even when the temperature of the molten resin is high.

  In order to achieve the above object, in the present invention, a cooling member is provided between the cylinder and the hot runner block.

  Specifically, a molded product manufacturing apparatus according to the present invention includes a fixed mold and a movable mold for molding a resin molded product, and a molded product manufacturing apparatus in which a cavity is formed by the fixed mold and the movable mold, A hot runner block formed with a first resin passage through which molten resin flows, a nozzle formed with a second resin passage communicating the first resin passage of the hot runner block and the cavity, and a second of the nozzle An opening / closing member that opens and closes the resin passage and a cylinder that drives the opening / closing member are provided, and the cylinder is attached to the hot runner block via a cooling member in which a passage through which a cooling medium flows is formed.

  It is preferable that a cooling circuit in which a cooling medium for cooling the resin in the cavity flows is formed in the fixed mold and the movable mold, and the cooling medium in the cooling circuit flows in the passage of the cooling member.

  The cooling medium may be water.

  A cylindrical collar is interposed between the cooling member and the hot runner block, and the collar is preferably formed of a heat insulating material.

-Action-
Next, the operation of the present invention will be described.

  When the opening / closing member is driven by the cylinder and the second resin passage of the nozzle is opened, the molten resin flowing through the first resin passage of the hot runner block passes through the second resin passage and is fixed and movable. Into the cavity between. When a predetermined amount of molten resin is supplied, the opening / closing member is driven by the cylinder to close the second resin passage. As a result, the supply of the molten resin into the cavity is stopped.

  At this time, the surface of the hot runner block is at a high temperature as the molten resin flows through the first resin passage inside the hot runner block. On the other hand, the cylinder is attached to the hot runner block via a cooling member. In this cooling member, for example, a cooling medium such as water circulates in a passage formed inside, so that heat transmitted from the hot runner block to the cylinder side is absorbed by the cooling medium. As a result, even if the temperature of the molten resin is high, the temperature rise of the cylinder can be suppressed.

  When a cooling circuit in which a cooling medium for cooling the resin in the cavity flows is formed in the fixed mold and the movable mold, the cooling medium in the cooling circuit is used to flow through the passage of the cooling member. It becomes possible. That is, it is not necessary to use a dedicated cooling medium for the cooling member.

  By interposing a cylindrical collar formed of a heat insulating material between the cooling member and the hot runner block, it is possible to reduce heat transmitted from the hot runner block to the cooling member side by the collar.

  According to the present invention, since heat transmitted from the hot runner block to the cylinder side can be absorbed by the cooling medium of the cooling member, even if the temperature of the molten resin flowing in the first resin passage of the hot runner block is high, The temperature rise of the cylinder can be suppressed. As a result, the life of the consumables used in the cylinder can be extended as much as possible, and the frequency of cylinder disassembly and parts replacement can be reduced.

  In addition, the cooling medium of the cooling circuit that cools the resin in the cavity is circulated through the passage of the cooling member, so that the cooling medium can be shared and effectively used. Further, by applying water as the cooling medium, the cylinder can be cooled easily and inexpensively.

  Furthermore, the heat | fever transmitted to a cylinder side from a hot runner block can further be reduced by comprising the color | collar interposed between a cooling member and a hot runner block with a heat insulating material.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following embodiment.

Embodiment 1 of the Invention
1 to 7 show an embodiment of a molded product manufacturing apparatus according to the present invention. FIG. 4 shows a cross section of the molded product manufacturing apparatus 1 in the pressurizing / cooling step. As shown in FIG. 4, the molded product manufacturing apparatus 1 is a device for manufacturing molded products such as bumpers and door trims for automobiles by injection molding, for example, an upper mold 11 that is a movable mold and a lower mold that is a fixed mold. A mold 10 composed of the mold 12 is provided.

  The lower mold 12 of the mold 10 is fixed and installed without being moved, and a recess 12a for forming one molding surface of the resin molded product is opened upward. On the other hand, the upper mold 11 of the mold 10 is disposed above the lower mold 12, and is formed with a molding portion 11a for forming the other molding surface of the resin molded product opened downward. The upper mold 11 is configured to be movable in the vertical direction. When the upper mold 11 is lowered and superposed on the lower mold 12, the upper mold 11 is positioned between the molded portion 11a of the upper mold 11 and the recess 12a of the lower mold 12. In addition, a cavity 13 for molding a resin molded product is formed.

  The mold 10 has a resin supply unit 15 for supplying molten resin into the cavity 13 and a cooling circuit (not shown) through which a cooling medium for cooling the resin in the cavity 13 flows. Yes. Water is applied as the cooling medium.

  Although not shown, the cooling circuit includes a cooling passage formed in the upper mold 11 and the lower mold 12 through which cooling water flows, a water storage tank, and a pump for circulating the cooling water. Then, in the step of pressurizing and cooling the resin supplied to the inside of the cavity 13, the resin pressurized in the cavity 13 is cooled by driving the pump and circulating the cooling water to the cooling circuit. ing.

  For example, a plurality of the resin supply units 15 are provided in an internal space 23 formed in the lower mold 12, and the molten resin is distributed and supplied from the plurality of resin supply units 15 to the inside of the cavity 13. Yes. As shown in an enlarged view in FIG. 1, the resin supply unit 15 includes a hot runner block 17, a gate nozzle 19 attached to the hot runner block 17, a gate pin 20 provided inside the gate nozzle 19, and a gate pin 20. And a cylinder 21 for driving the motor.

  The hot runner block 17 has a substantially rectangular parallelepiped shape, for example, and is installed in the internal space 23 of the lower mold 12 so as to extend in the horizontal direction (left and right direction in FIG. 4). A first resin passage 16 through which the molten resin flows is formed in the hot runner block 17 so as to extend in the horizontal direction. One end of the first resin passage 16 is connected to a port 24 provided on the side surface of the lower mold 12. For example, as schematically shown in FIG. 5, a resin injection device 27 is connected to the port 24.

  The injection device 27 includes a main body portion 29 having a resin heating chamber 28 therein, an introduction portion 31 for introducing a pellet-shaped resin 30 into the heating chamber 28, and a screw portion 32 provided inside the heating chamber 28. I have. A heater 33 is provided on the surface of the main body 29. Thus, the resin 30 introduced into the heating chamber 28 from the introduction portion 31 is heated by the heater 33 and stirred by the screw portion 32, and supplied from the tip of the main body portion 29 to the first resin passage 16 of the hot runner block 17. Like to do.

  As shown in FIG. 1, the lower mold 12 is formed with a vertical hole 23a that connects the internal space 23 and the cavity 13, and the gate nozzle 19 is disposed in the vertical hole 23a. Yes. As shown in FIG. 1, the gate nozzle 19 is configured by a cylindrical body in which a second resin passage 18 extending in the vertical direction is formed, and is mounted on the upper surface of the hot runner block 17. The lower end of the second resin passage 18 is connected to the first resin passage 16 of the hot runner block 17.

  On the other hand, the upper end of the vertical hole 23a is filled with a spool bush 35 so as to seal the interface with the vertical hole 23a. The spool bush 35 is formed with a third resin passage 36 connected to the upper end of the second resin passage 18 and extending vertically. The inner diameter of the lower end portion of the third resin passage 36 is smaller than that of the second resin passage 18. That is, the resin passage is narrowed at the lower end of the third resin passage 36. On the other hand, the third resin passage 36 is formed in a tapered cross section whose inner diameter increases upward. The upper end portion of the third resin passage 36 constitutes a resin supply port 37 to the cavity 13. Thus, the second resin passage 18 is configured to communicate the first resin passage 16 and the cavity 13 via the third resin passage 36.

  A through hole 39 is formed in the lower surface of the hot runner block 17 at a position below the second resin passage 18. The through hole 39 is filled with a gate pin guide 40 so as to prevent resin leakage from the first resin passage 16. The gate pin guide 40 is formed with a hole 41 extending in the vertical direction.

  The gate pin 20 is inserted through the second resin passage 18 and through the hole 41 of the gate pin guide 40 through the first resin passage 16. The upper end of the gate pin 20 is tapered and closes the second resin passage 18 by contacting the lower end of the third resin passage 36, while being separated from the lower end of the third resin passage 36. 2 The resin passage 18 is opened. That is, the gate pin 20 constitutes an opening / closing member that opens and closes the second resin passage 18.

  On the other hand, the lower end of the gate pin 20 is connected to the cylinder rod 43 of the cylinder 21. The cylinder 21 is a hydraulic cylinder and is mounted on the lower surface side of the hot runner block 17. Then, by driving the cylinder 21, the gate pin 20 is moved forward and backward. The cylinder 21 has a seal member (not shown) provided at a sliding portion such as the cylinder rod 43. A general fluorine-based packing is used for the seal member. Of course, a heat-resistant hydrogenated nitrile system can be used as the material of the seal member. As a result, the frequency of replacement of the seal member can be reduced.

  A mounting plate 44 is mounted on the upper portion of the cylinder 21. The mounting plate 44 is fixedly attached to the lower surface of the hot runner block 17 by bolts or the like via a cooling plate 45 that is a cooling member and a rectangular cylindrical collar 46. In other words, the cylinder 21 is attached to the hot runner block 17 via the cooling plate 45. The mounting plate 44 is preferably made of a heat insulating material. A collar 46 is interposed between the cooling plate 45 and the hot runner block 17.

  As shown in FIG. 2 which is a perspective view and FIG. 3 which is a cross-sectional view, the cooling plate 45 is formed of a rectangular plate-like member and a passage 48 through which water as a cooling medium flows.

  A through-hole 49 through which the cylinder rod 43 of the cylinder 21 slides is formed at the center of the cooling plate 45. In addition, bolt holes 50 are formed at the four corners of the cooling plate 45, respectively. As shown in FIG. 3, the passage 48 has two straight holes 48a drilled inward from one side surface of the cooling plate 45, and a side surface adjacent to the side surface on which the two straight holes 48a are formed. It is constituted by one straight hole 48b drilled into the inside. The straight hole 48 b is closed by the plug 51. The cooling circuit of the mold 10 is connected to the passage 48 of the cooling plate 45 so that the cooling water of the cooling circuit always flows.

  The collar 46 is made of a heat insulating material, and although not shown, four bolt holes corresponding to the bolt holes 50 of the cooling plate 45 are formed. By providing the collar 46, a predetermined movable length of the cylinder rod 43 can be ensured.

  With the above configuration, the resin supply unit 15 opens and closes the second resin passage 18 by the vertical movement of the gate pin 20 driven by the cylinder 21, and the first resin passage 16 of the hot runner block 17 supplied from the injection device 27. The molten resin is supplied from the supply port 37 into the cavity 13 of the mold 10 through the second resin passage 18 and the third resin passage 36.

  Next, with reference to FIGS. 5-7, the manufacturing process which manufactures a molded article with the said molded article manufacturing apparatus is demonstrated. The manufacturing process includes a molten resin supply process, a shaping process, and a pressurization / cooling process.

  In the molten resin supply process, as shown in FIG. 5, the resin melted by the injection device 27 is supplied into the recess 12 a of the lower mold 12 with the upper mold 11 raised and the mold 10 opened. In the injection device 27, the pellet-shaped resin 30 is introduced into the heating chamber 28 from the introduction portion 31, stirred by the screw portion 32, heated by the heater 33, and sent to the front port 24 side. The resin melted in the heating chamber 28 is introduced into the resin supply unit 15 in the lower mold 12 through the port 24.

  In the resin supply unit 15, as shown in FIG. 1, the molten resin introduced from the port 24 to the first resin passage 16 of the hot runner block 17 flows into the second resin passage 18. Thereafter, the cylinder 21 is driven to move the gate pin 20 downward, thereby opening the second resin passage 18 closed by the gate pin 20. Then, a predetermined amount of molten resin is supplied from the second resin passage 18 into the recess 12 a of the lower mold 12 through the third resin passage 36 and the supply port 37.

  Next, in the shaping step, the resin supplied to the recess 12a of the lower mold 12 is added between the molded portion 11a of the upper mold 11 and the recess 12a of the lower mold 12 by lowering the upper mold 11. Press and spread. As a result, the inside of the cavity 13 formed between the upper mold 11 and the lower mold 12 is filled with the resin.

  Subsequently, in the pressurizing / cooling step, the resin in the cavity 13 is pressurized by further pressing the upper mold 11 downward. At the same time, the cooling water is circulated through the cooling circuit (not shown) of the mold 10 to cool and harden the resin in the cavity 13. Thereafter, the upper mold 11 is raised and the molded product is taken out from the mold 10. A molded article is manufactured by the above steps.

-Effect of Embodiment 1-
Therefore, according to the first embodiment, since the cooling plate 45 is interposed between the cylinder 21 and the hot runner block 17, the cooling conducted from the hot runner block 17 to the cylinder 21 side through the passage 48 of the cooling plate 45. Can be absorbed in water. As a result, even if the temperature of the molten resin flowing in the first resin passage 16 of the hot runner block 17 is high, the temperature rise of the cylinder 21 can be suppressed, so that the seal member used for the cylinder 21 is long. The service life can be extended, and the frequency of disassembling the cylinder 21 and replacing parts can be reduced. That is, the movement of the resin supply unit 15 is ensured, and labor and time required for maintenance can be reduced.

  For example, when glass fiber is mixed in the molten resin, the resin temperature is as high as about 240 ° C. to 260 ° C. Even in this case, the temperature of the cylinder 21 is increased to about 30 ° C. The temperature can be kept down.

  Further, since the temperature rise of the cylinder 21 can be suppressed, a general and inexpensive fluorine-based material can be applied to the sealing member of the cylinder 21, and the cost required for maintenance can be reduced. Moreover, even if it is a case where the some molded product from which the temperature of molten resin differs by applying the structure of this manufacturing apparatus, it is not necessary to change the material of the sealing member of the cylinder 21 for every molded product. . That is, regardless of the temperature of the molten resin, it is possible to unify the device structure and reduce spare parts.

  In addition, the cooling water of the cooling circuit provided for cooling the resin in the cavity 13 is circulated through the passage 48 of the cooling plate 45 so that the cooling water can be shared and effectively used. Can do. In addition, by applying water as a cooling medium, the cylinder 21 can be cooled easily and inexpensively.

  Furthermore, since the collar 46 interposed between the cooling plate 45 and the hot runner block 17 is formed of a heat insulating material, the heat transmitted from the hot runner block 17 to the cylinder 21 can be further reduced.

<< Other Embodiments >>
In the first embodiment, the collar 46 is formed of a heat insulating material. However, the collar 46 may be formed of a steel material, and the heat insulating material may be interposed between the collar 46 and the mounting plate 44 as a separate member. A cooling circuit unique to the cooling plate 45 may be provided separately in the passage 48 of the cooling plate 45. Moreover, although water was used as a cooling medium, it is possible to apply oil etc. in addition to that, for example. The lower mold may be a movable mold and the upper mold may be a fixed mold.

  As described above, the present invention is useful for a molded product manufacturing apparatus that manufactures a molded product by injection molding, and is particularly suitable for suppressing the temperature rise of a cylinder as much as possible.

It is sectional drawing which shows the structure of a resin supply part. It is a perspective view which shows the external appearance of a cooling plate. It is sectional drawing which shows the channel | path in a cooling plate. It is sectional drawing which shows the structure of a molded article manufacturing apparatus. It is sectional drawing which shows schematically the molded article manufacturing apparatus and injection apparatus in a molten resin supply process. It is sectional drawing which shows schematically the molded article manufacturing apparatus and injection apparatus in a shaping process. It is sectional drawing which shows schematically the molded article manufacturing apparatus and injection apparatus in a pressurization and cooling process. It is sectional drawing which shows the resin supply part of the conventional molded article manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Molded article manufacturing apparatus 11 Upper mold | type 12 Lower mold | type 13 Cavity 16 1st resin channel | path 17 Hot runner block 18 2nd resin channel | path 19 Gate nozzle (nozzle)
20 Gate pin (opening / closing member)
21 Cylinder 45 Cooling plate (cooling member)
46 Color 48 passage

Claims (4)

A molded product manufacturing apparatus comprising a fixed mold and a movable mold for molding a resin molded product, wherein a cavity is formed by the fixed mold and the movable mold,
A hot runner block in which a first resin passage through which a molten resin flows is formed;
A nozzle formed with a second resin passage communicating the first resin passage of the hot runner block and the cavity;
An opening and closing member for opening and closing the second resin passage of the nozzle;
A cylinder for driving the opening and closing member,
The molded product manufacturing apparatus, wherein the cylinder is attached to the hot runner block through a cooling member in which a passage through which a cooling medium flows is formed. In claim 1,
A cooling circuit in which a cooling medium for cooling the resin in the cavity flows is formed in the fixed mold and the movable mold,
The molded article manufacturing apparatus, wherein the cooling medium of the cooling circuit flows through the passage of the cooling member. In claim 1 or 2,
The molded product manufacturing apparatus, wherein the cooling medium is water. In any one of Claims 1-3,
A cylindrical collar is interposed between the cooling member and the hot runner block,
The said color | collar is comprised with the heat insulating material, The molded article manufacturing apparatus characterized by the above-mentioned.

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